"Quasar." Microsoft Encarta 96 Encyclopedia. Microsoft Corporation. Funk & Wagnalls Corporation. 1993-1995
"Quasar." Compton's Interactive Encyclopedia. SoftKey Multimedia Inc. 1994, 1995, 1996.
"Quasars and Active Galaxies." Chandra X-ray observatory. February 23, 2000. <htttp://chandra.harvard.edu/xray_sources/quasars.html>. (July 15, 2000)
"Quasar 3C 273." Chandra X-ray Observatory. February 23, 2000. <http://chandra.harvar.edu/xray_sources/3c273/index.html>. (July 15, 2000)
Berger, Melvin. Quasars, Pulsars, and Black Holes in Space. GP Putnam's Sons. 1977
"Chandrasekhar, Subramanyan." http://www.infoplease.com/ce6/A0811326.html
"Star." Microsoft Encarta 96 Encyclopedia. Microsoft Corportation. Funk & Wagnalls Corporation. 1993-1995
Miller, Chirs. "Neutron Stars and Pulsars." September 1998. <http://www.eclipse.net/~cmmiller/BH/blkns.html> . (July 25, 200)
Miller, Chris. "How Black Holes and Neutron Stars Form?" September 1998.<http://www.eclipse.net/~cmmiller/BH/blkform.html> (July 25, 200)
"Neutron Stars." Chandra X-ray Laboratories. November 4, 1998. <http://chandra.harvard.edu/xray_sources/neutron_stars2.html> (July 15, 2000)
"Neutron star." extracted from infoplease.com . <http://www.infoplease.com/ce6/sci/A0835336.html> (August 5, 2000)
Begelman, Mitchell. Gravity's fatal attraction:Black Holes in the Universe. Scientific American Library. 1996
Pickover, Clifford A. Black Holes: A traveller's guide. John Wiley & Sibsm Inc. 1996. p.
Ferguson, Kitty. Prisons of Light: Black Holes. Cambridge University Press. 1996
Benet, Jim. "Mr. Galaxy's Supernovae" <http://www.chapman.edu/oca/benet/mrgalaxy.htm>
Tyler, Pat. "Supernova" <http://legacy.gsfc.nasa.gov/docs/snr.html> (25 February, 2000)
"HST Public Pictures" <http://oposite.stsci.edu/pubinfo/Pictures.html>
Snyder, Doug. "Nebulae Simplified" <http://www.blackskies.com/neb101.htm> (February, 2000)
"HST Public Pictures" <http://oposite.stsci.edu/pubinfo/Pictures.html>